Ligand-directed tosyl chemistry for protein labeling in vivo.

Here we describe a method for the site-selective attachment of synthetic molecules into specific 'endogenous' proteins in vivo using ligand-directed tosyl (LDT) chemistry. This approach was applied not only for chemically labeling proteins in living cells, tissues and mice but also for constructing a biosensor directly inside cells without genetic engineering. These data establish LDT chemistry as a new tool for the study and manipulation of biological systems.